A sheriff in the US state of Ohio has told local residents to be careful where they buy their heroin, after a reported case involving the Russian flesh-eating drug krokodil.

Athens county sheriff Patrick Kelly broadcast his unorthodox message on a local TV station after seeing a needle drug user covered in scaly marks.

Kelly told 10TV he was convinced the user had injected herself with krokodil, whose name is a reference to its corrosive properties which can turn skin into reptilian scales.

Krokodil is an opioid, like heroin, but far more deadly. Some experts are concerned that drug vendors are selling the former as a cheaper alternative to the latter.

Kelly said: "I'm hoping that they [drug users] won't use heroin at all, but I'm not that naive. To say 'get your heroin from a trusted source' sounds ridiculous coming from a sheriff.

"But if you're going to have to get your fix, you're not going to want to get ahold of krokodil."

To date, America's Drug Enforcement Administration has refused to confirm the presence of krokodil in the US, despite several reported cases.

The drug has been cited in several US states including Illinois, Arizona, Oklahoma, Nevada and New York, as well as in Canada. However Rusty Payne, a spokesman for the DEA, told IBTimes UK there is as yet nothing to suggest the presence of krokodil.

"DEA is aware of and tracking the nation-wide reports of alleged abuse of the controlled substance desomorphine that is found in the drug krokodil, a homemade substitute for heroin invented and used in rural Russia, Georgia, Ukraine, and Kazakhstan.

"DEA is investigating the matter by acquiring samples alleged to contain desomorphine, interviewing drug abusers, and monitoring intelligence reports. To date, none of our forensic laboratories has analysed an exhibit found to contain desomorphine.

"A sample sent to our Chicago forensic laboratory that was suspected to be krokodil was actually heroin."

Payne also told us that, given the obvious dangers of krokodil and the widespread publicity surrounding its spread, users "get what they deserve" if they choose to take it.